The present disclosure relates to control systems for power machines, such as skid steer loaders. More particularly, the present disclosure relates to a control system for a power machine that provides variable resolution of the adjustable controls for fine positioning.
Power machines include a number of work vehicles such as skid steer loaders. Skid steer loaders in general have a frame that supports a cab and a movable lift arm that supports a work tool such as a bucket, a forklift, or the like. The movable lift arm is coupled to the frame with power actuators such as hydraulic cylinders. In addition, the tool is coupled to the lift arm by one or more hydraulic cylinders. An operator manipulating the skid steer loader manipulates the tool by actuating the hydraulic cylinders. Skid steer loaders also commonly have an engine that drives a hydraulic pump to power hydraulic traction motors. The traction motors are commonly coupled to wheels through a drive mechanism to move or drive the skid steer loader.
Power machines also include an actuator for directing the speed of the vehicle, i.e., an adjustable speed controller. One example of an adjustable speed controller is a joystick on the skid steer loader that can be used to direct both the speed and course of travel. The user can manipulate the adjustable speed controller over a range of motion to direct the skid steer loader to operate over a range of speed.
Some loaders are provided with a user input for causing the loader to be operated in a selected one of two ranges of speeds. For example, if loader has been rented to a novice user, the rental dealer may wish to set the speed to a lower speed. Similarly, where a loader is attached to a sensitive tool, such as a forklift, and the user is approaching a pallet, the user may wish to switch the operation of the loader into a slower, less responsive mode that allows for finer positioning. By contrast, when a user is simply driving down a road, the user may wish to control loader in a higher speed mode. Therefore, some loaders have been provided with a selector that can be manipulated to select between a low-speed and a high-speed mode.